1. Field of the Invention
This invention relates to a panel shutter device, and more particularly to a device for securing a continuously moving shutter curtain carrying a number of panels in both closing and opening operations and for insuring safety at the time of lowering the panel by the construction in which a plurality of panels forming the shutter curtain are suspended by connecting chains, and an opening in the wall of a building is closed and opened by a continuous movement of the curtain panels with both lifting shifts and lateral shifts by means of reversible sprockets.
2. Brief Description of the Prior Art
In this description of the term "continuous moving", and like terms, is intended to mean the sequential movement of panels from vertical movement in vertical guide means to horizontal movement into the storage housing along horizontal guide means, and vice versa.
Conventional panel shutters are constructed in such a way that roller shafts projecting on both side surfaces of the upper panels of a plurality of panels are connected by means of respective connecting chains to form a shutter curtain. When these curtains are drawn into a housing as the curtain is opened, the loose portions of the connecting chains are suspended by being meshed with sprockets disposed in the housing on rails provided for back and forth (horizontal) movement at both right and left sides in the housing case. The housing case is disposed on upper end portions of guide rails erected on both sides of the opening of the building, and the shutter curtain is lifted or lowered by interlocking with the reversible motion of the sprockets to open or close the opening portion of the building.
When the sprockets are turned clockwise, each panel closing the opening, by being disposed at equal intervals in vertical flat form along the guide rails, is lifted in the vertical direction by means of the connecting chains, and guide rollers journalled on the roller shafts projecting on both side surfaces of each panel are shifted upwardly by being guided within the guide rails. Moreover, the guide rollers of the top panel is continuously carried onto the horizontal housing rails, positioned on the inner right and left side plates of the housing case, through a sequential continuous movement process by action of the sprockets. Each panel, as it reaches the top, is laterally shifted along with the rolling of the guide rollers, and when all panels are disposed in the housing case, and the bottom surface of the bottom panel is upwardly shifted and is aligned with the bottom surface of a lintel portion of the housing, the lifting is stopped.
Also, when the rotation of the sprockets is reversed, the bottom panel descends and shifts along the guide rails, and each panel journalled on the housing rails in the housing case laterally shifts on the housing rails sequentially, and each panel shifts to the guide rails sequentially from the lower end side of the panel due to the continuous movement process of the sprockets, and each panel descends and shifts along the guide rails where they become suspended on the connecting chains, and each panel is disposed again in vertical flat formation, being supported by the guide rail to close the opening of the building.
This type of panel shutter, performing an opening or closing operation as described in the foregoing, advantageously does not cause friction or a collision between the panels or between the panel and the guide rails at the time of opening or closing of the shutter curtain, and thus they do not produce an uncomfortable noise as compared with a lifting shutter of an even earlier prior art take-up system in which the top and bottom edges of an elongate steel slab are journalled and connected in the vertical direction to form a shutter curtain. This type of shutter curtain is rolled up by means of a take-up shaft mounted rotatably in the housing case, or is rewound to open or close the opening of a building. Prior art shutter curtains of the first type gain recognition for their excellent function by shops in underground areas where sounds are resonated easily or by shops in housing areas, and where there is a demand for an optimum shutter curtain design. However, the conventional shutter has the following drawbacks with respect high speed operation and also with respect to safety during opening or closing.
In view of the continuous movement property of the panels, the panel shutter of this kink of prior art shutter curtain was constructed in such a way that in the continuous movement process, the panels were carried continuously on to the housing rails after being released from the guide rails, or were continuously carried from the housing rails to the guide rails again. Since the shifting direction of the panel was converted from horizontal movement to vertical movement where the upper end of the panel is now suspended, the lower end side of the panel became the free end, and the panel was free to swivel or swing in the back and forth direction with the roller shaft acting as a fulcrum. By the inertia motion, and when this swinging action occurs the lower side of the panel can get hooked on the housing or guide rails, and the panel cannot be continuously carried on the housing rails or the guide rails resulting in the inability of proper ascending or descending, whereby an accidental breaking the panel occurs. The swinging amplitude became bigger in proportion to the opening or closing speed, and also the size of width of the opening, namely, the problem is aggravated in proportion to the mass of the panels, particularly, by the collisions of the mutual panels rolling on the housing rails. In such a case, the continuous movement became impossible, and the shutter curtain mechanism was unable to deal with the opening or closing of the shutter curtain at a high speed.
Under the circumstances, a method of providing a guide shaft at the lower end side of the panel and providing a guide member to guide the guide shaft and to introduce it to the guide rails was used. But this type of shutter curtain apparatus was still unable to deal with the high speed opening or closing of the shutter curtain which resulted in a collision between the guide shaft and the guide member. This shutter curtain apparatus could not eliminate the problem, and a panel shutter device capable of dealing with the high speed opening or closing was demanded from users.
As to safety, the panel shutter of this kind was constructed in such a way that each panel forming the shutter curtain was positioned at equal intervals in the vertical direction and connected by means of the connecting chains, so that when the opening in the building was closed, in a process where each panel was sequentially placed on the panel beneath it there was a danger of injury by pinching a finger inadvertently in the gap between each panel. As a result, as a safety countermeasure for preventing finger pinching, methods were developed for using a lifting chain connected to the bottom panel and separating the mutual panels just before coming to the housing case, thereby avoiding creating a gap between each panel at the time of lifting or shifting, as disclosed in the official gazettes, Japanese Utility Model Laid-open Publication No. Sho 62-88087 or Japanese Utility Model Laid-open Publication No. Sho 62-94293 previously filed by the present applicant, Japanese Utility Model Laid-open Publication No. Sho 63-1195, or Japanese Patent Laid-open Publication No. Sho 63-55298. However, these methods not only brought about problems of requiring reinforcement of the connection to the bottom panel and to the bottom panel itself due to the application of the full load of all the panels on the connecting portion of the lifting chain including the bottom panel, but also, the methods required a special guide rail for guiding the lifting chain. Because of this requirement, if the panel shutter was large in size, a higher degree of reinforcement of the connection and the bottom panel had to be made according to the larger size, so that, for example, in a large size building that had an opening to be installed with a normal panel shutter, a height of which was more than a double the height of the ordinary opening, the installation of a conventional panel shutter with the finger pinching avoidance structure was regarded impossible.
Accordingly, the present invention has been conceived to eliminate the drawbacks of the conventional panel shutters and to secure high speed continuous operation during opening of closing, and to secure the safety of operation during opening or closing. It is a primary object to provide a panel shutter device in which a forced guide mechanism is provided to guide the panel forcedly from the guide rail to the housing rail or from the housing rail to the guide rail smoothly. The smoothness of the continuous movement of the panels in both ascending and descending movement prevents hooking of succeeding panels even if the panel shutter is made to open or close at a high speed.
Another object of this invention is to provide a panel shutter device in which, in order to secure safety against finger pinching during the operation of placing each panel on panels beneath it during the time of descending of the shutter curtain, each panel is suspended by a connecting chain by means of a support shaft without using a lifting chain that is directly suspended from a bottom panel, and each panel is lifted without causing a gap on each panel of the shutter curtain, in spite of the foregoing construction, and there is no need of providing the lifting chain separately which, accordingly, eliminates the necessity of reinforcement of the connection to the bottom panel that bears the total load of the panels or of providing a special guide rail to guide the lifting chain, and thus, the feature of avoiding finger pinching is realized with a relatively simple construction.
Still another objection of this invention is to provide a panel shutter device capable of avoiding finger pinching even in a panel shutter device capable of smooth continuous movement of the panels at high speed opening or closing of the shutter curtain.